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Zama appraisal exceeds expectations for Talos

Partnership 'delighted' with results of well as it upgrades resource estimates and turns an eye to development solutions for structure off Mexico

Talos Energy has provided an upbeat assessment of the potential of its Zama discovery off Mexico after finishing its Zama-3 appraisal with results that it said had exceeded expectations.

The US independent said it now pegged the discovery in the "upper half" of its earlier recoverable resource estimate between 400 million and 800 million barrels of oil equivalent.

Partner Premier Oil now puts its gross estimate at a proven resource of 670 million boe, probable resource of 810 million boe and possible resource as high as 970 million boe.

"We are delighted with the results of the latest Zama appraisal well, which — together with the positive results from the earlier appraisal wells — has caused us to significantly upgrade our resource estimates of the Zama structure," Premier chief executive Tony Durrant said.

He added that the data showed better-than-expected reservoir properties, including a higher net-to-gross ratio, better porosity and increased hydrocarbon saturation.

"Our focus now turns to selecting the optimal development for the field, ahead of taking a final investment decision next year," Durrant said.

The Zama-3 well was designed to test the southern extension of the discovery, and was drilled by the semi-submersible EnscoRowan 8503. Previously the consortium drilled the Zama-2 appraisal well in addition to a sidetrack that was flow-tested.

Operator Talos said it is pushing ahead with unitisation talks with state oil company Pemex as well as early front-end engineering and design work.

Talos is aiming to work towards the goal of taking a final investment decision in 2020, according to chief executive Tim Duncan.

"Based on the preliminary results of our appraisal programme, we have confirmed the combination of outstanding subsurface properties, significant recoverable volumes and attractive economic potential that have already made Zama a globally recognised asset," Duncan said.

He added that the match of the preliminary well data to the company's geophysical model suggests that a gross recoverable resource in the upper half of the pre-appraisal guidance range of 400 million to 800 million boe.

Consistent with the previously drilled discovery well and appraisal well, the probe logged about 1000 feet (305 metres) of gross true vertical depth sand and 748 feet of gross total vertical depth pay-bearing section, which matched expectations for the southern part of the area.

"The well was drilled downdip of the Zama-1 well, allowing the well to penetrate the oil-water contact in the southern portion of the field, consistent with the geophysical flat spot seen throughout the downdip edge of the reservoir," Talos said.

The net-to-gross pay ratio for the discovery matched that of the prior wells, in Zone 3 exceeding expectations at between 85% and 90%. The company considers Zone 3 and 4 to contain most of Zama's resource potential.

Talos collected another massive core sample of 717 feet with 99% recovery, even larger than samples collected from prior wells.

The company's appraisal programme was finished 39 days early and under budget, and without any lost-time incidents or environmental issues.

The third partner, Wintershall Dea, also expressed readiness to progress towards the development stage.

"We are very pleased with the results of the entire appraisal campaign," chief technology officer Hugo Dijkgraaf said.

"It confirms the significant recoverable volumes of this world-class discovery. Zama is an outstanding asset that offers very attractive opportunities. Together with our partners we are now looking forward to select the best development concept for the field."

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